The proposed research has two principle objectives: To further develop and refine behavioral procedures for studying the interaction of olfaction and gustation in the elaboration of learned consumatory behavior and to further assess the contribution of gustatory neocortex to the orchestration of adaptive behavior guided by gustatory cues. A combination of behavioral and neurological procedures are utilized in the following general approach: Appropriate behavior techniques and measures are first developed and refined using normal rats and then neurological manipulations are utilized to explore the contribution of relevant brain areas to the behaviors under study. The first objective is in the behavioral assessment stage: Rats are injected with a drug (e.g. cyclophosphamide) producing toxicosis following consumption of a fluid in the presence of a novel, distinctive odor; the fluid either contains a distinctive taste cue (quinine, acid, salt or sucrose) or it does not (plain water). The dependent measure taken subsequent to the above training procedure in extinction is either amount consumed of plain water in the presence of the relevant odor alone or amount consumed of the taste stimulus without the odor. Comparisons between groups provide measures of the degree of interaction of taste and odor in the elaboration of learned aversions to either component alone, and comparisons between odors and between tastes yield indications of the discriminative specificity of such aversions. The second objective is in the neurological manipulation stage: Following ablation of gustatory neocortex taste preference tests are conducted to determine the sensitivities of lesioned rats to several taste stimuli as compared to normal rats, and the associative strength of these stimuli is assessed in a discrimination learning paradigm in which a specific cue is paired with toxicosis. The subsequent degree of aversion to that cue is assessed relative to other distinctive taste cues and relative to the performances of normal rats and rats with control lesions. Lesions are assessed histologically by surface and retrograde degeneration criteria.